Cement Hill Water Treatment Plant CA4810005 Tracer
Description: Cement Hill Water Treatment Plant CA4810005 Tracer Study July 30, 2020 By Guy Schott, P.E Table of Contents Clearwell Design Specifications and Tracer Sampling Points Summary of Tracer Results and Procedures Tracer Injection Point Recorded
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slide1. Cement Hill Water Treatment Plant CA4810005 Tracer Study July 30, 2020 By Guy Schott, P.E<br>
slide2. Table of Contents Clearwell Design Specifications and Tracer Sampling Points
Summary of Tracer Results and Procedures
Tracer Injection Point
Recorded Tracer Data (Tables)
Graphs: Modified Step-Dose Curves for Stations 2 and 3
Graphs: Normalized Modified Step-Dose Curve to F-Curve for Stations 2 & 3
Purpose of a Tracer Test
Disinfection Exposure Time of Fluid in Vessel for Determining Ct10
Ct10 Value
Baffling Factor (BF), Definition
Tracer Test Method (Modified Step-Dose)
Method of Analysis and Equipment<br>
slide3. Pipeline & Tank Design Specifications<br>
slide4. Summary of Tracer Procedures Tracer study was conducted on a 3,189 linear feet, 20-in diameter transmission and two 2.0 MG storage tanks all operated in series. Liquid fluoride was used as the tracer and was injected into a 20-in pipeline downstream of filtration.
Sampling were done at three stations
Station 1: End of 3,189 linear feet transmission line to determine fluoride dose (mg/L)
Station 2: Outlet of 2.0 MG Steel Tank
Station 3: Outlet of 2.0 MG Concrete Tank
Pipeline flow was 3,000 gpm (steady-state)
Tanks exit flows varied from 2,200 – 2,400 gpm<br>
slide5. Cement Hill Water Treatment Plant Tracer and Fluoride injection location Tracer: H2SiF6, Fluoride (F)
Feed pump rate: 100 mL/min
Background: 0.081 mg/L as F
Measured dose: 2.1 mg/L as F (excluding background fluoride)
Fluoride (tracer) was injected into a 20-in diameter transmission pipe (post filtration). The transmission line is 3,189 linear feet to the CT storage tanks.<br>
slide6. Tracer Test Result Summary – Transmission Line + 2.0 MG Steel Tank Modified Step-Dose
Test Date: 7/30/20
Transmission Line: 3,189 feet (20-in Dia)
Transmission Line Vol: 52,044 gallons
Transmission Flow: 3,000 gpm
Tank Operating Level: 21.2 - 21.6 ft
Tank Working Vol: 1,258,326 gallons (avg) Volume of Transmission Line + Tank: 1,310,370 gallons (avg)
Steel Tank Outlet Flow: 2,390 gpm (avg)
HRT: 548 minutes (1,310,370 gal/2,390 gpm)
t10: 38 minutes
Baffling Factor (t10/HRT): 0.07<br>
slide7. Tracer Test Result Summary – Transmission Line + 2.0 MG Steel + 2.0 MG Concrete Tanks Modified Step-Dose
Test Date: 7/30/20
Transmission Line: 3,189 feet (20-in Dia)
Transmission Line Vol: 52,044 gallons
Transmission Flow: 3,000 gpm
Tank Operating Level: 21.2 - 22.7 ft
Combined Tanks Working Vol: 2,583,606 gallons (avg) Volume of Transmission Line + Tanks: 2,635,651 gallons (avg)
Concrete Tank Outlet Flow: 2,214 gpm (avg)
HRT: 1,183 minutes (2,635,651 gal/2,214 gpm)
t10: 270 minutes (4.5 hours)
Baffling Factor (t10/HRT): 0.23<br>
slide8. Station 1: Transmission Line to 2.0 MG Steel Tank First segment is 3,189 linear feet of 20-inch diameter transmission line to 2 MG Steel tank. Tracer dose (Fluoride) is measured and verify as it enters the first CT storage tank.<br>
slide9. Station 2: 2.0 MG Steel Tank Sample station on exit side of 2.0 MG Steel Tank. This water exits the tank and flows to the bottom of the 2.0 MG Concrete Tank.
Baffling Factor (t10/HRT): 0.07
(Pipeline + 2.0 MG Steel Tank) operated in series<br>
slide10. Station 3: 2.0 MG Concrete Tank Sample station on exit side of 2.0 MG Concrete Tank.
Baffling Factor (t10/HRT): 0.23
(Pipeline + 2.0 MG Steel Tank + 2.0 MG Concrete Tank) operated in series<br>
slide11. Tracer Fluoride Pipeline Station 1, Table 1<br>
slide12. Tracer Fluoride Pipeline Station 1, Table 2<br>
slide13. Tracer Dose and Background Residual Average background fluoride concentration: 0.081 mg/L as F
Average steady-state measured fluoride concentration exiting pipeline and entering the first tank (steel): 2.179 mg/L as F
Fluoride dose: 2.179 – 0.081 = 2.10 mg/L as F
Results are based on tracer dose of 2.10 mg/L as F
10% of tracer dose is 0.210 mg/L as F<br>
slide14. Tracer Fluoride Steel Tank Station 2, Table 1<br>
slide15. Tracer Fluoride Concrete Tank Station 3, Table 1<br>
slide16. Tracer Fluoride Concrete Tank Station 3, Table 2<br>
slide17. Tracer Fluoride Concrete Tank Station 3, Table 3<br>
slide18. Step-Dose Curve 20-in Dia. Transmission Line (3,189 ft)<br>
slide19. Step-Dose Curve Transmission Line + 2.0 MG Steel Tank Dose: 2.1 mg/L
0.21 mg/L at t10
t10: 38 min
HRT: 548 min t10/HRT = 0.07<br>
slide20. Normalized to F-Curve Transmission Line + 2.0 MG Steel Tank Baffling Factor (BF) = 0.07<br>
slide21. Step-Dose Curve: Transmission Line + 2.0 MG Steel + 2.0 MG Concrete Tanks Dose: 2.1 mg/L
0.21 mg/L at t10
t10: 270 min
HRT: 1,183 min t10/HRT = 0.23<br>
slide22. Normalized to F-Curve : Transmission Line + 2.0 MG Steel + 2.0 MG Concrete Tanks Baffling Factor (BF) = 0.23<br>
slide23. Purpose of a Tracer Study To determine the hydraulic efficiency or disinfectant exposure time of water through one or more reactors.
The addition of known quantities of a nonreactive chemical (tracer) is added in the form of a pulse (slug) or step-input.
The time of travel or disinfectant exposure time through the reactor is related to:
Flow rate
Reactor water volume
Water Depth
Reactor configuration
Hydraulic mixing<br>
slide24. Disinfection Exposure Time of Fluid in Vessel for Determining Ct10 C” is the disinfectant residual (mg/L) at the point of inactivation compliance.
The disinfection exposure time of water used for Ct10 calculation is the time (t10) it takes for the first 10 percent of the water entering the reactor to exit the reactor.
To determine this, a marker (nonreactive tracer) is introduced into the water and is monitored leaving the reactor.
Example: 2.7 mg/L of tracer is continuously dose during testing; t10 is that time when 0.27 mg/L of tracer concentration (10% of dose) has exit the reactor.<br>
slide25. Ct10 Value Log inactivation is based on the Delivered Dose, “Ct10”
“C” is the disinfectant residual (mg/L)
“t10” is the exposure or contact time (minutes)
Multiply them:
C • t10 = mg/L • min (delivered dose)
The calculated Ct10 value is looked up in EPA Ct tables to determine the log inactivation based on specific monitoring parameters (pH, disinfectant residual and temperature).<br>
slide26. Baffling Factor (BF) Baffling factor or short-circuiting factor:
Determined from tracer study or estimated
BF = t10/ HRT from tracer study
HRT (hydraulic residence time) = reactor volume divided by reactor flow
Once the BF is determined, then it is applied to the operations of the reactor for determining the disinfectant exposure time.
Example:
Total Clearwell operating volume: 2,600,000 gallons
Exit flow: 2,500 gpm (3.6 MGD)
BF: 0.23, from tracer study
Calculated contact or disinfection exposure time:
2,600,000 gal ÷ 2,500 gpm × 0.23 = 239 minutes = t10<br>
slide27. Test Method Modified Step-Dose Method
It is a continue feed of tracer at constant rate and inlet plant flow throughout the duration of the test. The “Step-Dose” test has a duration of 3-4 HRT to achieve reactor outlet steady-state tracer concentration. The time “t10” is determined when 10% of the tracer dose concentration has exist the reactor. The “Modified Step-Dose” test allows the test to be completed in less than 1 HRT by physical measurements of the tracer inlet flow and/or channel basin concentration.<br>
slide28. Method of Analysis and Equipment Intellical™ ISEF121 Fluoride (F-) Ion Selective Electrode (ISE)
HQ40d Portable ISE Multi-Parameter Meter
Fluoride Ionic Strength Adjustor (ISA)
Fluoride Standards (0.2/2.0 & 0.5/ 5.0 mg/L)
25 mL graduated cylinder
Finnpipette F2 variable volume pipette, capacity 0.5 - 5 mL
Electrode stirrer stand
50 mL beakers
Stir Bar, Magnetic, Polygon<br>
slide29. Contact Guy Schott, P.E.
State Water Resources Control Board
Division of Drinking Water
Santa Rosa, CA
Go to Tracer Test Results for review
www.waterboards.ca.gov/drinking_water/programs/districts/mendocino_district.html
Email: Guy Schott - Guy.Schott@waterboards.ca.gov
Office Number: 707-576-2732<br>
slide2. Table of Contents Clearwell Design Specifications and Tracer Sampling Points
Summary of Tracer Results and Procedures
Tracer Injection Point
Recorded Tracer Data (Tables)
Graphs: Modified Step-Dose Curves for Stations 2 and 3
Graphs: Normalized Modified Step-Dose Curve to F-Curve for Stations 2 & 3
Purpose of a Tracer Test
Disinfection Exposure Time of Fluid in Vessel for Determining Ct10
Ct10 Value
Baffling Factor (BF), Definition
Tracer Test Method (Modified Step-Dose)
Method of Analysis and Equipment<br>
slide3. Pipeline & Tank Design Specifications<br>
slide4. Summary of Tracer Procedures Tracer study was conducted on a 3,189 linear feet, 20-in diameter transmission and two 2.0 MG storage tanks all operated in series. Liquid fluoride was used as the tracer and was injected into a 20-in pipeline downstream of filtration.
Sampling were done at three stations
Station 1: End of 3,189 linear feet transmission line to determine fluoride dose (mg/L)
Station 2: Outlet of 2.0 MG Steel Tank
Station 3: Outlet of 2.0 MG Concrete Tank
Pipeline flow was 3,000 gpm (steady-state)
Tanks exit flows varied from 2,200 – 2,400 gpm<br>
slide5. Cement Hill Water Treatment Plant Tracer and Fluoride injection location Tracer: H2SiF6, Fluoride (F)
Feed pump rate: 100 mL/min
Background: 0.081 mg/L as F
Measured dose: 2.1 mg/L as F (excluding background fluoride)
Fluoride (tracer) was injected into a 20-in diameter transmission pipe (post filtration). The transmission line is 3,189 linear feet to the CT storage tanks.<br>
slide6. Tracer Test Result Summary – Transmission Line + 2.0 MG Steel Tank Modified Step-Dose
Test Date: 7/30/20
Transmission Line: 3,189 feet (20-in Dia)
Transmission Line Vol: 52,044 gallons
Transmission Flow: 3,000 gpm
Tank Operating Level: 21.2 - 21.6 ft
Tank Working Vol: 1,258,326 gallons (avg) Volume of Transmission Line + Tank: 1,310,370 gallons (avg)
Steel Tank Outlet Flow: 2,390 gpm (avg)
HRT: 548 minutes (1,310,370 gal/2,390 gpm)
t10: 38 minutes
Baffling Factor (t10/HRT): 0.07<br>
slide7. Tracer Test Result Summary – Transmission Line + 2.0 MG Steel + 2.0 MG Concrete Tanks Modified Step-Dose
Test Date: 7/30/20
Transmission Line: 3,189 feet (20-in Dia)
Transmission Line Vol: 52,044 gallons
Transmission Flow: 3,000 gpm
Tank Operating Level: 21.2 - 22.7 ft
Combined Tanks Working Vol: 2,583,606 gallons (avg) Volume of Transmission Line + Tanks: 2,635,651 gallons (avg)
Concrete Tank Outlet Flow: 2,214 gpm (avg)
HRT: 1,183 minutes (2,635,651 gal/2,214 gpm)
t10: 270 minutes (4.5 hours)
Baffling Factor (t10/HRT): 0.23<br>
slide8. Station 1: Transmission Line to 2.0 MG Steel Tank First segment is 3,189 linear feet of 20-inch diameter transmission line to 2 MG Steel tank. Tracer dose (Fluoride) is measured and verify as it enters the first CT storage tank.<br>
slide9. Station 2: 2.0 MG Steel Tank Sample station on exit side of 2.0 MG Steel Tank. This water exits the tank and flows to the bottom of the 2.0 MG Concrete Tank.
Baffling Factor (t10/HRT): 0.07
(Pipeline + 2.0 MG Steel Tank) operated in series<br>
slide10. Station 3: 2.0 MG Concrete Tank Sample station on exit side of 2.0 MG Concrete Tank.
Baffling Factor (t10/HRT): 0.23
(Pipeline + 2.0 MG Steel Tank + 2.0 MG Concrete Tank) operated in series<br>
slide11. Tracer Fluoride Pipeline Station 1, Table 1<br>
slide12. Tracer Fluoride Pipeline Station 1, Table 2<br>
slide13. Tracer Dose and Background Residual Average background fluoride concentration: 0.081 mg/L as F
Average steady-state measured fluoride concentration exiting pipeline and entering the first tank (steel): 2.179 mg/L as F
Fluoride dose: 2.179 – 0.081 = 2.10 mg/L as F
Results are based on tracer dose of 2.10 mg/L as F
10% of tracer dose is 0.210 mg/L as F<br>
slide14. Tracer Fluoride Steel Tank Station 2, Table 1<br>
slide15. Tracer Fluoride Concrete Tank Station 3, Table 1<br>
slide16. Tracer Fluoride Concrete Tank Station 3, Table 2<br>
slide17. Tracer Fluoride Concrete Tank Station 3, Table 3<br>
slide18. Step-Dose Curve 20-in Dia. Transmission Line (3,189 ft)<br>
slide19. Step-Dose Curve Transmission Line + 2.0 MG Steel Tank Dose: 2.1 mg/L
0.21 mg/L at t10
t10: 38 min
HRT: 548 min t10/HRT = 0.07<br>
slide20. Normalized to F-Curve Transmission Line + 2.0 MG Steel Tank Baffling Factor (BF) = 0.07<br>
slide21. Step-Dose Curve: Transmission Line + 2.0 MG Steel + 2.0 MG Concrete Tanks Dose: 2.1 mg/L
0.21 mg/L at t10
t10: 270 min
HRT: 1,183 min t10/HRT = 0.23<br>
slide22. Normalized to F-Curve : Transmission Line + 2.0 MG Steel + 2.0 MG Concrete Tanks Baffling Factor (BF) = 0.23<br>
slide23. Purpose of a Tracer Study To determine the hydraulic efficiency or disinfectant exposure time of water through one or more reactors.
The addition of known quantities of a nonreactive chemical (tracer) is added in the form of a pulse (slug) or step-input.
The time of travel or disinfectant exposure time through the reactor is related to:
Flow rate
Reactor water volume
Water Depth
Reactor configuration
Hydraulic mixing<br>
slide24. Disinfection Exposure Time of Fluid in Vessel for Determining Ct10 C” is the disinfectant residual (mg/L) at the point of inactivation compliance.
The disinfection exposure time of water used for Ct10 calculation is the time (t10) it takes for the first 10 percent of the water entering the reactor to exit the reactor.
To determine this, a marker (nonreactive tracer) is introduced into the water and is monitored leaving the reactor.
Example: 2.7 mg/L of tracer is continuously dose during testing; t10 is that time when 0.27 mg/L of tracer concentration (10% of dose) has exit the reactor.<br>
slide25. Ct10 Value Log inactivation is based on the Delivered Dose, “Ct10”
“C” is the disinfectant residual (mg/L)
“t10” is the exposure or contact time (minutes)
Multiply them:
C • t10 = mg/L • min (delivered dose)
The calculated Ct10 value is looked up in EPA Ct tables to determine the log inactivation based on specific monitoring parameters (pH, disinfectant residual and temperature).<br>
slide26. Baffling Factor (BF) Baffling factor or short-circuiting factor:
Determined from tracer study or estimated
BF = t10/ HRT from tracer study
HRT (hydraulic residence time) = reactor volume divided by reactor flow
Once the BF is determined, then it is applied to the operations of the reactor for determining the disinfectant exposure time.
Example:
Total Clearwell operating volume: 2,600,000 gallons
Exit flow: 2,500 gpm (3.6 MGD)
BF: 0.23, from tracer study
Calculated contact or disinfection exposure time:
2,600,000 gal ÷ 2,500 gpm × 0.23 = 239 minutes = t10<br>
slide27. Test Method Modified Step-Dose Method
It is a continue feed of tracer at constant rate and inlet plant flow throughout the duration of the test. The “Step-Dose” test has a duration of 3-4 HRT to achieve reactor outlet steady-state tracer concentration. The time “t10” is determined when 10% of the tracer dose concentration has exist the reactor. The “Modified Step-Dose” test allows the test to be completed in less than 1 HRT by physical measurements of the tracer inlet flow and/or channel basin concentration.<br>
slide28. Method of Analysis and Equipment Intellical™ ISEF121 Fluoride (F-) Ion Selective Electrode (ISE)
HQ40d Portable ISE Multi-Parameter Meter
Fluoride Ionic Strength Adjustor (ISA)
Fluoride Standards (0.2/2.0 & 0.5/ 5.0 mg/L)
25 mL graduated cylinder
Finnpipette F2 variable volume pipette, capacity 0.5 - 5 mL
Electrode stirrer stand
50 mL beakers
Stir Bar, Magnetic, Polygon<br>
slide29. Contact Guy Schott, P.E.
State Water Resources Control Board
Division of Drinking Water
Santa Rosa, CA
Go to Tracer Test Results for review
www.waterboards.ca.gov/drinking_water/programs/districts/mendocino_district.html
Email: Guy Schott - Guy.Schott@waterboards.ca.gov
Office Number: 707-576-2732<br>